Temperature controlling apparatus



Jan. 16,1934. u s 1,943,965

TEMPERATURE A CONTROLLING APPARATUS Original Filed Sept. 26, 1930 IN VEN TOR El -a X $4.... 69-M-1- C-JZ ATTORNEYS Pa ented Jen; 16, 19 34 I l ",943,965

UNITE STATES PATENT OFFICE 1,943,905 TEMPERATURE con'raommo APPARATUS George E. Hulse, New Haven, Conn assignor to The Safety Car Heating '& Lighting Company, a corporation of New Jersey Application September 26, 1930, Serial No. 484,541

Renewed September 20, 1933 "31 Claims. (01. 257-3) This invention relates to temperature controled within a chamber or space 28, the walls of ling apparatus, and with regard to the more which are diagrammatically indicated at 29. specific features thereof, to such apparatus of the It will thus be seen that upon the temperature motor driven type. 4 of the chamber 28 rising to a predetermined and 5 Among the objects of the invention are the proadjustable value, the consequent expansion of the 60 v vision of practical'apparatus of the above nature thermostatic cell 27 will swing the arm 23 into of simple and dependable construction, and such enga With the Contact 20 and Complete the a paratus in which the action is efficient to a high circuit above described through the megrietie degree. Another object is to provide apparatus clutch 14, thus Connecting Compressor. 15 with 1 of the above nature which is adapted to meet efthe engine wh h m y b assumed t be in Confectively widely varying conditions of use. Other tinllells op e Apparatus is connected as objects are to provide apparatus of the above y Suitable Conduits 30 w a cooling C l 31 nature which is economically operated and in Positioned in the ehemberh 0011, p n pwhich the response to varying conditions is rapid; Deretlle 15 becoming p i tends to du e Other objects will be in part obvious and in part the e p atur f the Chamber 28, and by m pointed out hereinafter. I traction of the thermostatic cell 27 interrupt the The invention accordingly consists in the fee.- circuit above described through t e ma netic tures of construction, combination of elements clutch- This interruption and consequent d y and, arrangement of parts whi h ill be l energization of the clutch 14 occurs when the P fled in the apparatus here after described, and temperature of the chamber has been reduced to the scope of the applicatio of hi h i be the desired value. It may here be noted that as dicated in the appended cl i I indicated at 32 the thermostat 27 is provided with The ac om anyi drawing i a diagl'ammatic an adjustment whereby it may become effective plan of one of various possible embodiments of the in governing the closing o t above circuit at ti I dlflerent predetermined values, thereby permit- Referring to this drawing in detail, the is ting an alteration of the temperatures at which it shown at 10 an engine which is preferably of the puts on and cuts Off thelrefrigeretihg ac io Diesel type having an exhaust conduit 11 and the AS the engine 10 is p f rably in continuous speed of whichiscontrolled by any suitable mech- Operation in Order to v id the necessity for 3 anism, diagrammatically indicated by 12. This automatic starting and pi pa atu i mechanism is such that upon the spring 13 being Pecomes important that its Speed be ver ed compressed, the governor or controller 12 will be accordance With q e ts of the condiset to maintain the engine's speed at an increased hone under w ich it is working. Normally the value and upon the endwise pressure on thi required refrigeration is proportional to the leakspring being relieved, the standard of speed of age P heat into the e ated space, and asthe engine will be lowered proportionately to this SumHPg the temperature of the etter to be subdecrease f pressure stantlally constant, this leakage W111 vary directly The engine 1018 connectedvby an electro with the outside temperature. There is accordnetic clutch 14 with refrigerating apparatus 15, mgly provldfad bulb 33 qutslde spaice connected with and controllm the ex ansion of preferably of the compression type This magg p netic clutch is of a well known type so that upon g g g s ggsfig g g t g: g gg current being lead through it, it will-beclosed controls the ex ansion of the thermos l and connect the engmelO with the compressor 15, The moving end of the cell 34 g g gfi 45 and upon this current being cut oi; will disconconnected as by a rod 5 with a lever 37 which heet these Pieces of h swings about pivot 38 which may for the present Engin it drives as t u t sp c c n be assumed tobe fixed. The lower end of lever 16 an electri generator 17, th xterna uit 37'bears two contacts 39 and 40 suitably insulated fromwhich leads through a conductor 18 to the from each other and from the lever as indicated. 50 clutch 14 and thence by a conductor 19 to a con- Thesecontacts are adapted respectively to engage tact 20. The remaining. terminal of the generator a contact ring'41 according as the lever 37 swings is connected through aconductor 21 and-the contoward the left or toward the right. Contact ductor 22 to a switch arm 23. .This switch'arm is ring 41 is mounted upon and insulated from'a nut pivoted as at 24 and connected by a rod 25 in- 42 and thus adapted to travel therewith continusulated' as at 26 with a thermostatic cell 27 mountously'making electrical contact with a stationary standard of speed will result.

member 43. The nut 42 is threaded upon a fixed shaft 44, and as itis rotated in one direction, tends to travel to compress the governing spring 13, a reverse direction of rotation relieving pressure thereon. This nut 42 is provided with a gear portion 45 continuously in mesh with an elongated pinion 46 mounted upon the shaft of a small motor 47. It will thus be seen that as motor 47 is rotated in one direction, the standard of speed of the engine 10 will be reduced, and as it is rotated in the opposite direction, an increased The field of this motor comprises coils 48 and 49 differentially wound and of substantially equal value; whereby upon these field coils being serially traversed by a current, they will neutralize each other and no motion of the motor will occur.- A circuit leads through the armature and differential field of this motor by a conductor 50 terminating at 51 at one of the motor terminals, and a conductor 52 leading from the field to a conductor 53 terminating at a fixed'contact 54. When the temperature of the'space 29 approaches the de-.

' sired temperature, the lower end of the swinging contact 23 will be in engagement with contact 54, thus completing the circuit from the latter through conductors 22 and 21 to the remaining terminal ofthe generator 17. With the current thus flowing, if either field coil 48 or field coil 49 be short circuited, the remaining coil will exert its effect and cause a rotation of the armature of motor 47 and a subsequent adjustment of the governor 12 as above described. If now it be assumed that the outside temperature is low with a low rate of heat leakage into the chamber 28, then the thermostatic cell 34 will be so contracted as to bring the contact 39 into engagement with contact 41. A short circuit is thus completed about the field section 49, this circuit comprising the above contacts and conductors 55 and 56. The shunting of field section 49 thereby formed will result in the rotation of the armature of motor 47 in such direction as to relieve the pressure upon the spring 13, thereby causing engine 10 to be governed to run at a reduced speed. This retraction or movement to the right of the nut 42 will carry the contact 41 away from the contact 39, although it is to be noted that if a further decrease of outside temperature were to occur, the

contact 39 would again contact the member 41 and cause a further lowering of the engine speed. It is, of course, to beunderstood thatupon the breakage of the circuit between contacts 39 and 41, the shunt about field section 49 will be broken and the motor 47 be stopped.

If it be assumed that there is a rise in the outside temperature, then the expansion of thermo static cell 34 will bring contact 40 into engagement with contact 41, thereby shunting the field section 48 by means of a circuit which leads by conductor 57 from contact 40 through a switch member 58 to'the. terminal of coil 48 opposite tothat which is connected with conductor 56. This short circuiting of field section 48 causes the field '49 to become afiected, resulting in the rotation of the motor 47 in the opposite direction, thereby compressing spring 13 and setting the standard of speed 01' the engine 10 at a higher value.

In this manner the rateof action of therefrigerating apparatus will be governed in accordance with the outside temperature acting upon the thermostatic bulb 33.

It is to be noted that when refrigeration starts, as for example when the chamber28 has recently been'packed with the goods to be refrigerated, it

If now the manually operated switches 59 and 61 outside temperature, there is provided a thermois desirable to bring these goods down to the standard cooling temperature at the earliest possible time, and this requires action of the engine 10 and consequently of compressor 15 at the highest speed. Such a condition would exist, for example, when the chamber 28 forms-the body of a refrigerator car, which has recently been loaded, demanding for best results this high speed of refrigeration even though outside temperature be low.

With this condition the thermostatic cell 27 is fully expanded, thus breaking the circuit between the lower end of the swinging contact 23 and the stationary contact 54. There is pro; vided, however, a switch 59 which upon closing will connect conductor 52 directly with conductor 21 and thereby short circuit the break at contact 54. There is also provided a short circuiting conductor 60 havingin circuit therewith a switch 61.

are temporarily closed, a shunt is formed about the field section 48 and current is supplied to field section 49 independently of the swinging contact 23. The motor 47 will thus be rotated in such direction as to compress the governors spring 13 to the fullest extent resulting in a maximum speed of the engine. With the parts in this condition manual switches 59 and 61 are opened and the apparatus continues to be operated atfmaxi- 'mum speed until the desired degree of coolness of 05 the chamber 28 is approached, at which time the swinging lever 23 will make contact with the member 54, and the automatic adjustment of the engine speed through contacts 39 and 40 will be resumed. Pre-cooling down to the proximity of the desired temperature'is thus attained in the shortest possible time.

As the temperature within the chamber 28 is a factor in the desired rate of cooling as well as the 315 static bulb 62 within the. chamber connected with a thermostatic cell or bellows 63, the active end of which is connected by a'lever 64 and link 65 with the pivot 38 of the lever 37. This pivotal point is thus under adjustment in accordance with the temperature of the chamber 28, and asthis temperature is maintained at a low standard,

cell 34 to bring the contact 40 into engagement with contact 41 and thereby increase the engine speed. I

If it is desired to vary this standard of action of the automatic mechanism by manual means, there is provided at the upper end of the lever 64 andpivotally connected therewith a threaded link 66 having an index point 67 co-acting with a suitable scale 68; the position of this link 66 may be manually adjusted by a knurled nut 69 threaded upon the link and resting within a slot 0 in a fixed member 70. I By adjustment of this nut 69 the position of thefpivot 38 may be brought to any desired point; the pivotal point thus adjusted may remain under the automatic action of thebellows 63, or if desired the latter may be rendered inoperative by closing a hand valve 71. The gas and vapor in the bellows 63 may be affected by the temperature'in the space in which it is located even though the valve 71 is closed. Thus in order to render this bellows absolutely inoperative when manual adjustment is desired at 70, a stationary set, screw 64--a is employed. when the valve '71 and the set screw 64-41 are closed, the position of the pivot 38 is wholly under control of the knurlednut 69.

In order to prevent operation ofthe system at maximum speed when no refrigeration is required and the outside temperature is high, there is provided a fixed contact 72 with which the upper end of lever'23 makes "engagement when the cell 27 is fully contracted. Uponthis engagement with contact 72, a circuit is completed from conductor 22 through a conductor 73, a

solenoid 74', and a conductor 75 to a point midway between the'field sections 48 and 49. This short,

circuits the field section 49 and causes the rotation of the motor 47 in such direction. as to relieve pressure upon thev spring 13 and set the governor 12 for lowest engine speed. In order that this action may not be interfered with by engagement of members 40 and 41 resulting in a short 'cirouiting of fleldsection 48, the solenoid .74 swings downwardly the spring'raised contact 58, thus breaking "connection between the spaced co-acting contacts 76 serially connected in the conductor 57. The engine speed is thus reduced to a minimum.

Under certain conditions the temperature within the chamber 28 may become unduly low, and .it may be desirable to prevent freezing of the goods stored thereini To bring this about a circuit is lead from the motor terminal 51 through a conductor 77 to a stationary contact 78 adapted upon contraction of the cell 34 due to its being subjected to-an outsidetemperature lower than that desired in the space 29 to make contact with a movable contact 79' mounted upon the oppo-, site end of the bellows. From contact 79 aconductor 80 leads through a solenoid 81, and thence by means of conductor 82 to the point 83 at which conductor 75 terminates.

The energization of the solenoid thus brought about attracts its core at and draws a' spring retracted piston valve 85 to the right. This valve normally held to the left by spring 86 directs the exhaust from the engine, past a valve 87 and thence out to the atmosphere at 88. When core 84 is attracted, however, the valve 87 is closed .against its seat and the valve 85 opened directing the exhaust through a device 89 in which it is brought into thermal relation with jackets 90 seriallyconnected with a conduit 91. The passage through this conduit leads past an expansion tank 92 to a heating coil 93 positioned in the chamber 28 and thence through a conduit 94 to the jackets 90. A suitable liquid is preferably contained in this heating system, and upon this liquid being heated by the exhaust as above set forth, a convection flow takes place which brings the temperature within the chamber 28above the undesirably low range.

It will thus be seen there is provided apparatus in which the most widely varying conditions of practical use are met with a maximum of efficiency, and that in this apparatus the various ob ects of this invention are achieved.

If the temperature in the compartment 28 becomes excessive, however, the thermostatic member 27 will expand, thus breaking the circuit between the switch 23 and the contact 72. This will break the circuit between the generator 17 and the solenoid 81, thus de-energizing this solenoid.

tion between the device 89 and the exhaust con- I duit '11 of the engine 10. It will be noted that at this time no refrigeration and no heating are taking place in compartment '28 for the switch 23 rests at a point midway between the contacts 20 and 72. Refrigeration will only take place when the temperature in this compartment rises sufiiciently to expand .thermostatic member 27 to a point where the switch 23 makes a circuit with the contact.20. Under the above mentioned conditions with the outside temperature unduly low, this will not occur because of a variable amount of heat leakage through the walls of the compartment 28. v j

As many possible embodiments may be made of the above invention, and as many changes may be made in the embodiment above set forth, it is ing relative pressure on said speed controlling I means by direction of rotation, a motor for rotating said pressure-exerting means, and temperature-responsive means for controlling the direction of rotation of said motor.

ture is to be regulated, a refrigerating unit. for said space, motive means for elements of said refrigerating unit, speed regulating means for said motive means, a motor, adjustable means for said speed regulating means actuated by said motor, and thermostatic means for controlling the actuation of said motor.

2. In a temperature regulating system, in coma bination, means forming a'space whose tempera- .3. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit for said space, motive means for elements of said re- A frigerating unit, speed controlling means for said motive means adjustable by relative pressure, a motor means for exerting different pressures on said speed controlling means actuated by said motor, and thermostatic means for controlling the actuation of said motor.

4. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit for said space, motive means for elements of said'refrigerating unit, speed controlling means for said motive means adjustable by relative pressure, means for exerting different pressures on said speed controlling means, and thermostatic means in said space and outside said space for regulating said controlling means.

5. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit operatively related to said-space, motive means for elements of said refrigerating unit, speed controlling means for said motive means controllable by relative pressure,pressure-exerting means to act on said speed controlling means, a motor for ling the actuation of said motor, and temperature responsive means'for adjusting the controlling action of said thermostatic means.

6. In a temperature regulating system, in combination, means forming a space whose tempe'rature is to be regulated, a refrigerating unit for said space, motive means for elements of said refrigerating unit, speed controlling means for said motive means controllable by relative pressure, pressure-exerting means to act on said speed controlling means, a motor for actuating said pressure-exerting means, thermostatic means for controlling the actuation of said motor, and manual means for adjusting the controlling action of said thermostatic means.

'7. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, at refrigerating unit for said space, motive means for elements of said refrigerating unit, speed controlling means for said motive means controllable by relative pressure, pressure-exerting means disposed to act on said speed controlling means, a motor for actuating said pressure-exerting means, thermostatic means outside said chamber for controlling the actuation of said motor, temperature responsive means inside said chamber for adjusting the regulating action of said thermostatic means, and manual means for adjusting the action of said thermostatic means on said motor and the action of said temperature responsive means on said thermostatic means.

8. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit for said space, motive means'for elements of said refrigerating unit, a clutch disposed between said motive means and said elements, speed regulating means for said motive means, thermostatic means for controlling said speed regulating means, and thermostatic means for controlling the actuation of said clutch.

9. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit for said space, motive means for actuating an element of said refrigerating unit, a clutch disposed between said motive means and said element adapted to connect said element with said motive means upon increase of speed, and automatic means controlling the speed of said driving means proportionately to the temperature within said space.

10. In a temperature regulating system, in combination, means forming a space whose temper ature is to be regulated, a refrigerating unit for said space, motive means for actuating an element of said refrigerating unit, a clutch disposed between said motive means and said element adapted to connect said element with said motive means upon increase of ,speed, and automatic means controlling the speed of said driving means proportionately to the difference between the temperatures within said space and surrounding said space.

11. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit for said space, motive means for actuating elements of said refrigerating unit, speed controlling means for said motive means adjustable by relative pressure, pressure-exerting means disposed to act on said speed regulating means, thermostatic means outside said chamber for controlling said pressure-exerting means, thermostatic means inside said chamber for adjusting the action of first thermostatic means, and manual means for adjusting the action of both of said thermostatic means.

12. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit for said space, a continuously running internal combustion engine actuating an element of said refrigerating unit, a clutch disposed between said engine and said element adapted to connect said element with said motive means upon increase of speed, a governor for said engine adjustable by relative pressure, means adapted to exert relative pressure on said governor according to the direction of rotation of said means, a motor disposed to actuate said means in either direction, thermostatic means regulating the direction of rotation of said motor, thermostatic means in said chamber for controlling the action of said first thermostatic means on said motor, manually operative means for regulating the action of said first thermostatic means on said motor, and thermostatic means in said chamber for controlling the actuation of said clutch.

13. In a temperature regulating system, in combination, means forming a space to be refrigerated, refrigerating apparatus operatively related to said space, means comprising a rotary motor adapted upon rotating in one direction to increase the effect of refrigeration, and upon rotation in the other direction to decrease said effect, and automatic means for controlling said motor.

14. In a temperature regulating system, in combination, means forming a space to be refrigerated, refrigerating apparatus operatively related to said space, means comprising a rotary motor adapted upon ro ating in one direction to increase the effect of refrigeration, and upon rotation in the other direction to decrease said effeet. and means in said space for controlling the direction of rotation of said motor.

15. In a tempera ure re ulatin system, in combination. means forming a space to be refrigerated. refri erating apparatus operatively related to said space. means comprising a rotary motor adapted upon rotating in one direction to increase the effect of refri eration and upon rotation in the other direction to decrease said effect. and means for con rollin the direction oi rotat on of said motor automatically regulated v the difference between the temperatures within said space and outside said space.

16. In a temperature regulating system, in combination. means forming a space whose temperature isto be re ulated. an internal combustion en ine in said ,svstem. heat absorbing means. means for tran ferring heat from said engine to said heat absorbing means, means for transferring heat from said heat absorbing means to said enclosing means. thermostatic means for regulating the flow of said heat to said absorbing means, and temperature responsive means adapted toact on said thermostatic means to limit the operation of said thermostatic means in accordance with the temperature conditions of said space.

1'7. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, an internal combustion engine in said system, heat absorbing means, means forconveying the heat from said engine .to said heat absorbing means, a valve disposed in said conveying means between said engine and said heat absorbing means, means for transferring said heat from said heat absorbing means to said space, thermostatic means for controlling the actuation of said valve, and a second thermostatic means for regulating the operation of said first thermostatic means in accordance with the temperature conditions of said space.

1 8. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit refrigerating unit,.heat absorbing means, means for transferring heat from said motive means to said heat absorbing means, means for transferring heat from said heat absorbing means to said space, and means controlling the speed of said motive means and said heat absorbing means pro,- portionately to the temperature within said space.

20. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit for said space, motive means for elements of. said refrigerating unit, heat absorbing means, means for transferring heat from said motive means to said heat absorbing means, means for transferring heat from said heat absorbing means to said space, speed controlling means for said motive means controllable by direction of rotation, a motor for rotating said speed controlling means in either direction, and means controlling the direction of rotation of said motor and the action of said heat absorbing means proportionately to the difference between the temperatures within said-space and outside said space.

21. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigerating unit for said space, motive means for elements of said refrigerating unit, heat absorbing means, means for transferring heat from said motive means to said heat absorbing means, means for transferring heat from said heat absorbing means to said space, speed controlling means for said motive means adjustable by direction of rotation, a motor for rotating said. speed controlling means in either direction, thermostatic means for selecting the direction of rotation of said motor, thermostatic means for limiting theaction of said first thermostatic means, and thermostatic means for regulating the action of said heat absorbing means. I

22. In a temperature regulating system, in'

combination, means forming a space whosetemperature is to beregulated, a refrigerating unit for said space, a continuously running internal combustion engine actuating the compressor of said refrigerating unit, an electro-magnetic clutch disposed between said engine and said compressor, heat absorbing means, means for transferring exhaustheat from said engine to said heat absorbing means, a valve disposed in said transferring means between said engine and said heat absorbing means, means for actuating said valve, meansfor transferring said heat from said heat absorbing means to said space, a governor for said engine adjustable by relative pressure, pressure-exerting means for said governor adjustable by the direction of its rotation, a motor for rotating said pressure-exerting means in either direction, thermostatic means :in said chamber for controlling the actuation of said clutch, thermostatic means outside said chamber for regulating the direction of rotation of said motor, said last -mentioned thermostatic means adapted to control the actuation of said valve actuating means and thermostatic means in said chamber for adjusting the operation of said second mentioned thermostatic means, said first mentioned thermostatic means adapted to limit the action of said motor. V

23. In a temperature regulating system, in

- combination, means forming a space whose temperature is to be regulated, an internal combustion engine, a heat exchange device, means connecting the exhaust manifold of said/engine with said heat exchange device, means for circulating a'fluid through said heat exchange device and into thermal contact with said space, and thermostatic means responsive to the temperature of said space for controlling said second-mentioned means, said thermostatic means also adapted to control the speed of operation of said engine.-

24.In' a temperature regulating system, in combination, means forming a space whose temperature isto be regulated, a' refrigeration unit for said space, an internal combustion engine adapted to drive certain parts of said refrigeration unit, said engine adapted torun continuously for the entire period of time when the temperature of said space is to be regulated whether or not said space needs refrigerating, a speed governor for selecting the operative speeds of said engine, a motor whoseactuation controls the action of said governor, and means responsive to the temperature inside said space for controlling the operation of said motor.

25, In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigeration unit for said space, an internal combustion engine adapted to drive certain; parts of said refrigeration unit, said engine adapted to run continuously for the entire period of time when the temsponsive to the temperature inside said space for modifying the action of said last-mentioned means.

26. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigeration unit for said. space, an internal combustion engine adapted to drive certain parts of'said refrigeration unit, said engine adapted to run continuously for the entire period of time when the temperature of said space is to be regulated whether or not said space needs refrigerating, a speed governor for selecting the operative speeds of said engine, a motor'whose actuation controls the action of said governor, means responsive to the temperature outside said space, and means responsive to the temperature inside said space,

IOU

tion unit, said engine adapted to run continuously for the entire period of time when the temperature of said space is to be regulated whether or not said space needs refrigerating, a speed governor for selecting the operative speeds of said engine, a motor whose actuation controls the action of said governor, means responsive to the temperature inside said space for controlling the operation of said motor, means responsive to the temperature outside said space for modifying the action of said last-mentioned means, and means responsive to the temperature inside said space for limiting the operation of said motor independently of the action of said last two-mentioned means.

28. In a temperature regulating system, in combination, means forming a space whose temperature is to be maintained at any one of a number of predetermined constant levels while the temperature outside said space fluctuates, said means allowing a greater amount of heat to leak therethrough into said space the further said outside temperature rises above the predetermined constant level, a refrigeration system adapted to act on said space, means responsive to the temperature inside said space for placing said system in operation when said inside temperature rises above the constant level being maintained, means for changing the operative standard of said last-mentioned means to change the temperature level being maintained, and means in direct thermal contact with and responsive to said fluctuations in said outside temperature adapted to increase the refrigerating rate at which said system removes heat units fromsaid space as said outside temperature rises above the constant level being maintained and. adapted to decrease the rate at which said system removes heat units from said space as said outside temperature falls toward the constant level being maintained, said second-mentioned means adapteed to coact with said last-mentioned means to change the standard of operation of said lastmentioned means when the temperature level being maintained is changed by said third-mentioned means.

29. In a temperature regulating system, in combination, means forming a space whose temperature is to be maintained at any one of a number of predetermined constant levels while the temperature outside said space fluctuates, said means allowing a greater amount of heat to leak therethrough into said space the further said outside temperature rises above the predetermined con stant level, a refrigeration system adapted to act? space as said outside temperature rises above the Y constant level being maintain and adapted to decrease the rate at which said system removes heat units from said space as said outside temperature falls toward the constant level being maintained, and means responsive to the temperature of said space adapted to change the operative standard of said last-mentioned means when the temperature level being maintained is changed.

30. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigeration unit for said space including a compressor, means responsive to the temperature of said space for control ling the operation of said compressor, means responsive to the temperature outside said space adapted to increase the refrigerating rate at which said system removes heat units from said space as said outside temperature rises and adapted to decrease the rate at which said system removes heat units from said space as said outside temperature falls, and means responsive to the temperature of said space adapted to coact with said last-mentioned means to change the operative standard of said last-mentioned means when a different temperature level is to be maintained in said space.

31. In a temperature regulating system, in combination, means forming a space whose temperature is to be regulated, a refrigeration unit for said space including a compressor, means responsive to the temperature of said space for controlling the operation of said compressor, means adapted to regulate the speed of said compressor in accordance with temperature conditions outside said space to increase the rate at which said system removes heat units from said space as said outside temperature rises and to decrease the rate at which said system removes heat units from said space as said outside temperature falls, and means responsive to the temperature of said space adapted to coact with said last-mentioned means to change theoperativestandard of said lastmentioned means when a difier'ent temperature level is to be maintained in said space.

GEORGE E.

CA l 

